mericon L. monocytogenes Kit

For real-time PCR detection of Listeria monocytogenes in food or animal feed

Highly sensitive and specific detection of L. monocytogenes DNA

Streamlined detection protocol

Dedicated mericon bacterial DNA isolation kits available

PCR run time of 73 minutes on the QIAGEN Rotor-Gene Q

Full license for PCR without additional costs

The mericon L. monocytogenes Kit is designed for the target-specific detection of L. monocytogenes DNA in food, animal feed, and pharmaceutical products. It is part of the AOAC-RI PTMSM-validated Listeria spp. detection workflow. The assay uses a real-time PCR-based protocol and forms part of the comprehensive QIAGEN food testing portfolio, which also features dedicated sample preparation kits and assays for ingredient authentication and GMO DNA detection. The mericon L. monocytogenes assay performs optimally on the Rotor-Gene Q, but has also been validated for block thermal cyclers.

The mericon L. monocytogenes Kit is intended for molecular biology applications in food, animal feed, and pharmaceutical product testing. This product is not intended for the diagnosis, prevention, or treatment of a disease.

Performance

The mericon L. monocytogenes Kit is for the specific detection of Listeria monocytogenes in enrichment cultures of food and animal feed samples. The assay can detect as few as 10 copies of L. monocytogenes DNA in a reaction and it exhibits high specificity for L. monocytogenes. In an experiment using 2500 copies of the tested DNA, no cross-reactivity was observed with other pathogens (see the table "Results of mericon L. monocytogenes Kit cross-reactivity study").

Results of mericon L. monocytogenes Kit cross-reactivity study

Pathogen

Result

Pathogen

Result

Listeria monocytogenes

+

Cronobacter sakazakii

–

Staphylococcus aureus

–

Bacillus cereus

–

Clostridium perfringens

–

Legionella erythra

–

Salmonella abony

–

Campylobacter jejuni

–

Yersinia enterocolitica

–

Legionella pneumophila

–

Shigella flexneri

–

VTEC stx1/stx2

–

Escherichia coli

–

Listeria seeligeri

–

Listeria innocua

–

Listeria welshimeri

–

Listeria ivanovii

–

Listeria grayi

–

Principle

The mericon L. monocytogenes Kit is designed for the qualitative detection of the human pathogenic bacteria Listeria monocytogenes in food and animal feed samples after enrichment. Listeria can be found in meat, raw vegetables, milk products, or seafood and can cause Listeriosis, a serious disease, leading to meningitis or sepsis.

Detection of pathogens using real-time PCR is based on the amplification of a specific region of the relevant pathogen genome. The amplified product is detected using target-specific fluorescent probes that bind to it. As the PCR product accumulates, there is an increased fluorescent signal from the bound probes. Monitoring the fluorescence intensities during the PCR run (i.e., in real time) allows the detection of the accumulating PCR product without having to re-open the reaction tubes afterward.

mericon PCR Assays include an internal control to control potential inhibition. This aids in the straightforward interpretation of the results (see the table "Summary of possible PCR outcomes").

The PCR primer set for each assay is highly specific and targets a unique and conserved region of the tested pathogen genome that has been bioinformatically and experimentally verified.

Summary of possible PCR outcomes

Internal control amplified

Tested DNA amplified

Meaning

+

+

Sample is positive for the target DNA

+

–

Sample is negative for the target DNA

–

–

PCR failed due to inhibition

Procedure

DNA is extracted from an enrichment culture of a sample of food or animal feed using a dedicated sample preparation kit. The mericon Bacteria Kit is for the isolation of bacterial DNA from Gram-negative bacteria. The mericon Bacteria Plus Kit is for the isolation of bacterial DNA from Gram-positive bacteria.

The isolated, pure bacterial DNA is assayed using a streamlined real-time PCR protocol that returns results in 73 minutes on QIAGEN's Rotor-Gene Q. The protocol has also been validated for use on other thermal block cyclers.

The results are displayed as easy-to-interpret PCR curves.

Applications

The mericon L. monocytogenes Kit is for real-time PCR-based detection of L. monocytogenes in food, animal feed, and pharmaceutical products.